1. Field of Invention
The present invention relates to a urea solution quality determining system for injecting a urea solution on an exhaust line for discharging a nitrogen oxide to reduce the nitrogen oxide and determining quality of the supplied urea solution to cope with the determination result.
2. Description of Related Art
As regulations on an exhaust gas of a vehicle are enhanced, an efficient nitrogen oxide reducing post processing device is required.
A selective catalyst reduction unit has the nitrogen oxide included in the exhaust gas react to ammonia to change the oxide nitrogen into a harmless material. In order to generate ammonia, urea is injected into the exhaust gas.
In particular, in a system for injecting a urea solution, quality of the urea solution is very important. In terms of on-board diagnostics (OBD), a method of sensing the quality of the urea solution to perform warning is required.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.